Hydrochlorothiazide belongs to the group of medications called diuretics. It is also an antihypertensive. It is used to decrease fluid retention (edema) caused by congestive heart failure, certain kidney or liver problems, and medications such as corticosteroids (e.g., prednisone) and estrogen. It is also used to lower high blood pressure. Hydrochlorothiazide works by making the body lose excess water and salt.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

To reduce fluid retention (edema), the usual recommended adult dose of hydrochlorothiazide is 25 mg to 200 mg daily. Some people may only need to take this medication every other day, or for 3 to 5 days per week, as directed by their doctor. For infants and children, the dose is based on body weight and is given in 2 divided doses.

For the treatment of high blood pressure, the usual recommended adult dose of hydrochlorothiazide is 12.5 mg to 50 mg daily.

When taken once daily, this medication should be taken in the morning to prevent the need to urinate during nighttime.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important that this medication be taken exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.